<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>徐中堂61</title>
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
<div id="app-3">
  <p v-if="seen">现在你看到徐中堂了</p>
</div>
<script>
    var app3 = new Vue({
        el: '#app-3',
        data: {
            seen: true
        }
    })
</script>

</body>
</html>
